Catheter-Associated Urinary Tract Infections in Adults: Diagnosis, Treatment, and Prevention
Urinary tract infections (UTIs) are among the most common healthcare-associated infections, and 70%-80% are catheter-associated urinary tract infections (CAUTIs). About 25% of hospitalized patients have an indwelling urinary catheter placed during their hospital stay, and therefore, are at risk for CAUTIs which have been associated with worse patient outcomes. Additionally, hospitals face a significant financial impact since the Centers for Medicare and Medicaid Services incentive program penalizes hospitals with higher than expected CAUTIs. Hospitalists care for many patients with indwelling urinary catheters and should be aware of and engage in processes that reduce the rate of CAUTIs. This article will discuss the diagnosis, treatment, and prevention of CAUTIs in adults.
© 2019 Society of Hospital Medicine
Every day in the United States, approximately 4% of patients in acute care hospitals have at least one hospital-acquired infection (HAI).1,2 Among the top 10 causes of death in the United States, HAIs are associated with increased morbidity, mortality, and hospital length of stay (LOS).2 The direct medical cost of treating HAIs is substantial for both hospitals and patients.3,4 Urinary tract infections (UTIs) are a leading cause of HAI, and 70%-80% of these are catheter-associated urinary tract infections (CAUTIs).5,6 In 2016, 26,983 CAUTIs occurred in acute care hospitals.7 The high incidence of CAUTI can substantially contribute to morbidity, length of stay, and mortality.8-11
The recognition that a substantial proportion of HAIs may be preventable, including 55%-70% of CAUTIs,12 has resulted in implementing multiple strategies to reduce CAUTI rates.13-17 These include simple prevention interventions such as avoiding placement of unnecessary indwelling urinary catheters and early removal of urinary catheters when they are no longer clinically indicated. Hospitalists are responsible for the care of many, if not most, inpatients with indwelling urinary catheters and are integral in antimicrobial stewardship efforts surrounding CAUTIs.18 Diagnostic stewardship, including appropriate urine specimen ordering, collection, processing, and reporting, works synergistically with antimicrobial stewardship and allows for appropriate antibiotic prescribing in symptomatic patients.19
DEFINITIONS
CAUTIs can be defined using either clinical or surveillance definitions. Clinical definitions are used at the bedside and take individual clinical characteristics into consideration, but vary among clinicians since there is no gold standard. Abnormal laboratory urinary findings in the absence of symptoms are not sufficient for the diagnosis of UTI, including CAUTI. Surveillance definitions, such as those used by the Centers for Disease Control and Prevention,20 are designed to be simple, easily applicable in any healthcare setting, and standardized to all patients. Surveillance definitions generally include at least one systemic or local symptom (such as fever or dysuria) and positive urine culture in a patient with an indwelling urinary catheter (or within 48 hours after its removal).
Pyuria is leukocytes or white blood cells (WBCs) in a urine specimen, with a threshold of >10 WBCs/high-power field using urine microscopy. The predictive value of different thresholds of pyuria for UTI is unclear.
Bacteriuria denotes the presence (on microscopy or culture) of bacteria in the urine. In a patient without signs or symptoms of a UTI, this is termed asymptomatic bacteriuria (ASB). A full discussion of bacteriuria, a major reason for inappropriate antibiotic use, is beyond the scope of this article but is discussed in a recent guideline.21
Urinary tract infections are usually characterized by a clinical syndrome along with evidence of pyuria and/or bacteriuria. The two major clinical syndromes that are observed are lower UTI (cystitis or bladder infections) and upper UTI (pyelonephritis or kidney infections). Rarely, patients may develop asymptomatic bacteremic UTI, where blood and urine cultures grow the same pathogen in the absence of clinical symptoms. (Table 1 summarizes the key points for these definitions).
